In many cities and towns, school systems are required to provide transportation to and from school for children living more than a specified distance from school. Generally this transportation is in the form of busing whereby school buses pick up school children at several bus stops along several bus routes and then deliver the children to their school. The arrival time of a school bus at a given bus stop can vary significantly from day to day for any of a number of reasons. As a result, children typically arrive at the bus stop well before the bus is expected to arrive to avoid missing the bus. These children frequently lack parental supervision. Furthermore, on inclement weather days, children waiting for their bus are exposed to harsh weather conditions including rain, snow, or extreme cold. To avoid this situation, concerned parents frequently wait with their children at the bus stop in a car, causing unnecessary pollution.
Buses can be delayed for numerous reasons including inclement weather, such as fog, snow, ice or extreme cold, which reduces the speed of the bus and thus impedes the arrival of the bus at the planned time. Similarly, bus mechanical problems, heavy traffic or substitute bus drivers can generate lengthy delays in bus arrival time. In addition, many school buses will make several sequential runs to pickup children for different schools such as the high, middle and grade schools for a town. A delay in picking up children in the first run can result in similar or longer delays for subsequent runs. Correspondingly, it is possible, when there is good weather and light traffic conditions, for the bus to arrive at the bus stop earlier than the planned time.
In areas where bus routes cover many miles there frequently is a large variance in arrival time of a bus at the bus stops along the route and in many instances the bus stop will not be visible from the home. Similarly in areas where children live closer together, frequently there are communal bus stops for several children such that the bus stop is not visible from the home of each child. Advance notification of bus arrival also allows time to prepare the children for school without rushing to catch the bus.
There are many other situations where passengers and their families might find advance bus notification information useful. Children with special needs will especially benefit from such information, as they will have adequate warning time by which to prepare for boarding of the bus. Additionally, all passengers will be relieved of the shock factor of a bus pulling up unannounced.
In addition the bus, or other transporting vehicle can be become delayed, misrouted, lost or otherwise go off a given travel route after passengers have boarded the bus for any of a number of reasons including the possibility of a driver intentionally departing from the assigned task and travel route for some unexplained reason. Thus, and in some situations, a bus might depart from the assigned travel route or run into vehicle problems after picking up passengers without the dispatching authority becoming aware for sometime afterwards. Because the driver does not provide a warning back to the dispatching authority, such situations are presently identified by someone at the delivery site, for example a school, noticing that a particular bus or vehicle has not arrived well after its expected arrival time or someone notices a bus has broken down and contacts the dispatching authority or police.
In the case where the potential problem is identified by someone noticing that the vehicle has not arrived at the delivery site, the responsible authorities typically dispatch another vehicle or the police to locate the missing vehicle, for example by backtracking along the assigned travel route. In the extreme case, where the driver has for some reason intentionally departed from the travel route, the responsible authorities would not become aware of this particular situation until sometime after an expected arrival time. Also, because of the lack of real-time location information the responsible authorities including the police have to perform a wide area search to track down such a vehicle. Further, there have been instances where a bus has traveled significant distances from the designated travel route before responsible law enforcement authorities caught up with the bus. Thus, in addition to advance notification of the arrival of the vehicle other situations have arisen where location tracking of buses, more particularly real-time tracking and monitoring of buses or other vehicles, would be beneficial for further assurances of passenger safety and would provide a mechanism for tracking down vehicles that are no longer in communication with a dispatcher.
There is disclosed in U.S. Pat. No. 4,325,057 a bus notification system wherein each bus transmitter emits a signal at a unique radio frequency to identify a specific bus. Each receiver is then tuned to the frequency corresponding to said bus transmitter and the length of time between notification and bus arrival is determined by adjusting the receiver's sensitivity control. When the receiver acquires the bus transmission above the predetermined sensitivity threshold the notification system is activated.
Similarly, there is disclosed in U.S. Pat. No. 5,144,301 an alert system using different radio frequencies to identify particular buses and receivers that are tuned to the appropriate radio frequency wherein the time to bus arrival is approximated by comparing the received signal strength to an adjustable threshold setting. When the received signal strength exceeds the threshold, the receiver sequentially activates visual and audio warning signals.
In U.S. Pat. No. 5,021,780, there is disclosed an arrival notification where each bus emits an encoded signal uniquely identifying the bus and receivers in homes along the route are adjusted prior to distribution to receive only the encoded signal transmitted by the bus. The alerting mechanism in the receiver is activated upon detection of the encoded bus transmission using signal strength to estimate arrival time. However, the receiver does not incorporate a method for adjusting the alerting mechanism sensitivity. As a result, there is no available means to control the delay time between notification and bus arrival. Additionally, since the receivers in homes are adjusted prior to distribution, any bus changes or household moves to new buses introduces additional logistics problems.
In these disclosures, the time to bus arrival is approximated by the strength of the bus transmission signal received at the household. Signal strength, however, may not be an accurate measure of distance in every case because obstructions in the wireless radio frequency path can further reduce the signal strength thereby tricking the distance calculation by the receiver. The reduced signal strength can significantly reduce the time period between notification of bus arrival and the actual arrival of said bus. In addition, if the bus route includes several streets that are in close proximity requiring the bus to double back to cover said streets; the possibility for premature notification arises. Further, if two adjacent school districts use the same radio frequency, false alarms and premature notifications can result from two buses in neighboring districts broadcasting the same radio frequency.
A complex advance notification system for alerting passengers when a vehicle is ahead of or behind schedule is disclosed in U.S. Pat. No. 5,400,020. In this system, a vehicle control unit compares the actual time at which the vehicle reaches a predetermined location along the vehicle route against the scheduled arrival time, where the vehicle location is determined by global positioning system (GPS) technology. If there is a discrepancy between the actual and scheduled time values, the vehicle control unit relays the time discrepancy to a base station control unit by wireless communication. The base station control unit notifies each passenger of the change in arrival time by telephone. Thus, arrival time notification only occurs if the vehicle is off schedule. Further, the notification system requires that the telephone line be open and a person present to receive the telephone call. If the passenger is unable to hear the telephone ring such as when the phone is already in use or when the passenger is outside awaiting the arrival of the vehicle, the notification system will fail.
Another complex system for notifying passengers waiting for public transit vehicles of the status of transit vehicles, including expected arrival times of vehicles at transit stops and arrival of connecting transit vehicles is disclosed in U.S. Pat. No. 6,006,159. The disclosed system determines the location of transit vehicles by using a GPS device. The vehicle location is transmitted to a central facility wherein the central processor generates a master transit table for all vehicles calculating scheduled stops, connections to other transit vehicles and arrival times at each scheduled stop. The master transit table is subsequently broadcast to display devices located throughout the geographic area of the transit system including display devices in vehicles and transit stops. The display device stores the transit table or a subset thereof and displays selected information. In addition, the transit table or a subset thereof can be received by portable display means such as pagers, computers or telephones.
This transit notification system is appropriate for city or regional public transportation systems where the system involves a large number of passengers who are traveling between any two transit stops within the transit system and a large number of transit vehicles which are traveling on numerous transit routes within a large geographic area. The central facility must have sufficient resources to process a continuous data feed from each vehicle in the system to form updated transit tables and broadcast the transit table over the entire geographic area of the transit system. This system of notification requires a significant investment of resources in infrastructure development including installation of the central processing center, smart display devices throughout the transit system and vehicle information units in the transit vehicles.
Many passengers predominantly use a transit system to travel between two points such as a commute between home and work. The portable display devices disclosed in this patent are capable of displaying arrival information for a vehicle at a selected vehicle stop, but they can not alert a passenger that a vehicle will arrive at said vehicle stop within a predetermined period of time. Frequently, an automated notification process is desirable to alert the passenger that it is time to start the commute. A device capable of alerting such a commuter of the exact time by which to leave for their commute prior to leaving their controlled environment would be ideal.
In U.S. Pat. No. 5,680,119, there is described a vehicle identification system wherein types of vehicles such as emergency, school bus or other public transportation, delivery or service vehicles with emitters transmit an identifiable signal corresponding to the vehicle type. This patent does not describe a method for identifying a unique vehicle of a particular class, but rather only a method for determining the type of vehicle. Thus, the system merely differentiates between a school bus and an ambulance.
A receiving unit acquiring a RF signal broadcast from a nearby vehicle containing the correct information that is not actually picking up passengers can incorrectly notify passengers of a vehicle arrival at a specified point along the vehicle route. For example, one common passenger pickup technique is to drive all the way to the end of a vehicle route and then commence picking up passengers from the end of the route. This pickup technique poses problems for passengers near the beginning of the route, who are passed by the vehicle traveling in the wrong direction a considerable time before their vehicle actually stops to pick them up. In another example, public transportation vehicles frequently stop at each station in both directions along the vehicle route. Incorporation of a direction of travel parameter into the information transmitted from a vehicle would be especially valuable, allowing a receiving unit to only activate an alert mechanism when receiving a transmission from the correct vehicle traveling in a specified direction.
It thus would be desirable to provide a notification system that can more accurately predict a precise time of vehicle arrival such that a passenger's waiting time for the vehicle is minimized. Such a notification system also should be less complex, less costly and not require extensive infrastructure as compared to prior art systems. Additionally, such systems and particularly the receivers therefore should be inexpensive and not require highly trained individuals to operate the equipment. Further, it would be desirable for such systems and particularly the receivers therefore to be easily adaptable to relocation of the receivers and/or changes in location of vehicles stopping points. Moreover, it would be desirable to provide a real-time monitoring or tracking system whereby the location of vehicles such as buses within a given area can be monitored or tracked in real-time so as to be capable of easily and quickly identifying vehicles that may be in trouble or that have significantly departed from the designated travel route. Also, it would be desirable to provide an integrated system that is capable of providing such notification and such real-time monitoring/tracking capabilities.